Players control an aquatic microorganism that evolves by consuming other microorganisms. The environment is made up of stacked two-dimensional planes that are visible below players current location and can be traveled between freely. The deeper the player goes, the more difficult the other microorganisms become. Most of the microorganisms are non-confrontational, and are composed of cells that increase the number of segments in the player's microorganisms when eaten. In rare cases, other microorganisms are aggressive, multi-segmented and only perish when all of their segments are eaten by the player's microorganisms; however, they can eat segments of the player's creature to regrow their own.